Did you know the first recorded dust explosion was observed in 1785 when Count Morozzo observed that clouds of grain dust came in contact with the flame of a mounted lamp? Explosions aren’t the only hazard associated with dust. It is a health risk associated with asthma, headaches, eczema, eye irritation and more.
Removing dust from the air is a priority indoors. Whether you are working in your home woodshop or on the floor of a modern industrial plant, a good filtration system is an important safety feature. The tried-and-true technology is the baghouse dust collector. These fabric filtration systems are versatile and one of the most popular dust filtration methods on the market today.
Read on to learn more.
Baghouse Dust Collector Overview
A baghouse or fabric filter is a particulate pollution control device that removes dust from the air. Power generation facilities, flour mills, pharmaceutical and chemical plants and other industries use baghouses to control emission of air pollutants. Homeowners use baghouses for their hobby woodshops, barns or anti-allergen filtration.
Baghouses typically are 99% (or better) effective at removing dust from the air, even when dust particles are very small.
These are the basic parts to any baghouse dust collector. Their appearance depends on design, but all fabric filters contain these components.
Filter Medium
These are the fabric bags and their support system. The bags can be made of felted or woven materials. The bags are typically long, cylindrical tubes. They can be supported at the top and bottom or have a frame inside. Dust is collected inside or outside the baghouse filter depending on the airflow design.
Fan
Dirty air is either pushed or pulled through the baghouse filter bag by a fan.
Bag Cleaner
Collected dust cakes onto the baghouse filter bag. It is removed from the fabric by shaking, reverse air, pulse jet, or sonic means. See more about this below.
Collection Hopper
Caked dust removed from the bag is temporarily stored for more convenient removal. There may be a vibration plate or similar to move the caked dust towards the discharge unit.
Discharge Unit
Large filters in an industrial setting have automatic discharge. Dust is automatically removed from the hopper and discarded using double dump devices, rotary airlock valves or similar. Smaller units for home use might have a drawer to empty.
How Your Dust Collector Works
Dust-laden air is drawn through an intake and directed to the filtration compartment. The air is pushed or pulled through the bags. Dust collects on the inside or the outside of the bag, depending on cleaning method. A layer of caked dust accumulates on the filter media surface.
When the filter bag no longer has sufficient pressure from the air, a sensor takes the unit offline (for some systems) and the cleaning process begins. When the compartment is clean, the system begins filtration again.
Filtered air exits on the other end of the system.
In a shaker-type unit, the airflow is periodically shut off and the dust is shaken off into the collection hopper.
In a reverse air filter, dirty air is pulled through the collector. The filter bag is supported by a metal frame to keep it from collapsing under pressure. Dust collects on the outside of the bags. For cleaning, a fan rotates and air is gently blown in reverse through the bag. This gently blows the caked dust off to fall into the collection unit. Some reverse air units can continue operation while this happens.
A pulse jet design uses high-pressure compressed air jets to shake caked dust off the filter bag. This method is very efficient and does not require that the filtration unit be offline to clean. However, it places stress on your filter bags and can require more frequent filter bag replacement.
A sonic cleaner uses sound waves to blast dust off the filter fabric. This method is very gentle and can increase the lifespan of your filter bags.
Dust collection equipment requires regular maintenance and filter replacement for maximum effectiveness.
Simple Checks to Maintain Efficiency
Regular maintenance of your filtration system ensures peak efficiency. Manufacturers provide recommend intervals for regular inspection and replacement of components.
1) Inspection/Maintenance: This consists of a schedule for regular
periodic inspections. These can be arranged as daily, weekly, monthly, semi-annual and annual tasks.
2) Differential Pressure: New filter bags have little air resistance as the pores of the fabric are not yet clogged with particles. As the fabric fills, the gauge registers the static resistance. Pressure drop is a good indicator of the dust that has collected on the filter and the condition of the filter.
3) Cleaning System: An effective cleaning system requires maintenance on its own schedule. Incomplete or ineffective cleaning results in dusty air released from the system, build-up in ductwork and premature wear of filter bags.
4) Collection Hopper Discharge: The hopper on a baghouse is not generally designed to store the collected dust. Dust remaining in the hopper leads to its return to the air or compaction that requires downtime to correct.
5) Filter Media: The most important item to check in a baghouse dust collector is the filter media. Periodic inspection of the filter bags is mandatory.
6) Structure and Ductwork: The structural integrity of equipment and ductwork for welds, joints, and seals affects performance. Any unexpected change in airflow can mean concerns for health.
Ask an Expert
We want you to know as much as you can about the proper operation and maintenance of your baghouse. With this basic guide, we can help you develop the right filter bags, screens and unique filtration program for your equipment and application.
We know many different industries and each has specific needs. Let us assist you with keeping your filtration equipment at peak efficiency and your downtime to a minimum. Contact our experienced technical designers today!
